Hi all,
Hope you can help me with understanding how Ruby / Rails treats arrays
full
of objects.
Let’s say I have to arrays of objects. Both are the same kinds of
objects.
tomatoes = Fruit.find(:all, :conditions => [ ‘tomato = ?’, true], :limit
=>
10)
fruits = Fruit.find(:all, :limit => 10)
And I want to create an array of these objects called @my_fruits, but I
don’t want the set to contain any duplicates.
In the Ruby API documentation for arrays it shows you can use the |
operator
to perform a union between two arrays, throwing out duplicates.
OK. That sounds good. That’s what I want.
@my_fruits = tomatoes | fruits
98% of the time I’ve found this works in my tests. I don’t get
duplicates.
But I’ve had instances where I do in fact have a row repeat.
Any ideas as to why the union operator doesn’t work in this case?
In my real world ™ example, I’m sorting the database rows randomly,
and
the data changes frequently. Both arrays contain the same types of
objects.
In entirely likely that two arrays can contain the same object.
Is there a performance hit in building an each loop on the likely
smaller of
the array to test whether the other array ".include?"s the object? Would
this be considered more reliable?
Example:
@my_fruits = fruits
tomatoes.each do | fruit |
@my_fruits.push(fruit) unless @my_fruits.include?(fruit)
end
Why?
Thanks.
D. Taylor S.,
Reality Technician